The present invention relates to multi-layer optical discs, and in particular relate's to a method of calculating an optimum value of a laser power for recording into a multi-layer optical disc.
In the case where information is recorded into an optical disc having an once-writable or rewritable multi-layer structure, a method of JP-A-2000-311346 is known as the method of adjusting the laser output during recording to an optimum recording power value with respect to a data area of a layer, to which information is written (Optimum Power Control, hereinafter, referred to as “OPC”).